The Siemens 3RT2037-3XF44-0LA2 is a size S2 SIRIUS contactor rated for 65 A at 480 V and 52 A at 600 V, making it a solid pick for switching motor loads in industrial control panels up to that current range. The coil is 110 V DC with spring-type terminals — no screw torque to verify, just strip and push.
Panel fit and clearances
Dimensions are 55 mm wide, 114 mm tall, 178 mm deep — the depth is the main thing to check against shallow enclosures.
Switching performance and ratings
Rated for AC-4 duty at 200 operations per hour maximum — that's the heavy inching/jogging cycle, not just continuous running. Arcing time is 10 to 20 ms, and the DC coil dropout time is 30 to 55 ms; the inrush current peak at coil pick-up is 1.5 A. Main contact ratings at 110 V DC: 1 A; at 220 V DC: 0.3 A; at 690 V: 1 A — these are the DC switching limits, not the AC motor ratings.